Russia will urge the United States to stick with the Iran nuclear deal at a meeting of the deal's signatories on the sidelines of a United Nations General Assembly session next week, Russia's UN envoy has said.

"That is not only our message, but the rest of the participants and those that are outside are trying to send this message across," Ambassador Vasily Nebenzya told reporters at the UN in New York on September 15.

A meeting of the parties to the agreement -- Iran, the United States, Russia, China, France, Germany, and Britain -- is expected on September 20.

The administration of U.S. President Donald Trump is currently reviewing the deal to determine whether it wants to continue honoring it. Thus far, the administration has adhered to the deal despite frequent sharp criticisms from Trump and his deputies.

"The Iran deal is one of the worst deals I've ever seen, certainly at a minimum the spirit of the deal is atrociously kept," Trump told reporters aboard Air Force One on September 14.

"It's a deal that should not have ever been made," Trump said. "You'll see what I'm going to be doing very shortly in October."